Is there a function that calculates the power of a
repeated-measure ANOVA design, e.g., 2 groups, 4
within-subject factors, an average 0.40 correlation between
the 4 within factors, etc.
I don't think I can use power.anova.test() because it does
not consider corr=0.40.
I am hoping that someone has already implemented the method
by Muller & Barton (1989, JASA 84: 549-555) on how to
approximate statistical power for a univariate test in
repeated-measures ANOVAs when the sphericity assumption is
not met. If not, perhaps the MANOVA approach by O'Brien &
Kaiser (1985, Psych Bull: 97, 316-33).
library(pwr) does not seem to support either.
Many thanks in advance,
Yuelin Li.
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Thomas Lumley
2011-Mar-10 19:25 UTC
[R] power for repeated-measures ANOVA lacking sphericity
On Fri, Mar 11, 2011 at 6:08 AM, Yuelin Li <liy12 at mskcc.org> wrote:> Is there a function that calculates the power of a > repeated-measure ANOVA design, e.g., 2 groups, 4 > within-subject factors, an average 0.40 correlation between > the 4 within factors, etc. > > I don't think I can use power.anova.test() because it does > not consider corr=0.40. >The easiest approach is likely to be simulation: simulate data from the design and compute the p-value, repeat a few thousand times. -thomas -- Thomas Lumley Professor of Biostatistics University of Auckland
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